1. Field of the Invention
The present invention relates to a lithography apparatus, and an article manufacturing method using the apparatus.
2. Description of the Related Art
Lithography apparatuses that perform writing on a substrate by controlling deflection scanning and blanking of charged particle beams such as electron beams are known. The lithography apparatuses may be employed as one of pattern forming technologies that is an alternative to optical exposure systems for the production or the like of a memory device of 4GDRAM or later with a line width of 0.1 μm or less. Here, since the lithography apparatus controls the scan position of an electron beam on a substrate using a deflector (scanning deflector), the relationship between a command value to be given to the deflector and the scan position of an electron beam needs to be accurately measured for improving writing accuracy. Japanese Patent Laid-Open No. 7-22303 discloses an electron beam lithography apparatus that estimates the scan position of an electron beam between reference marks from the time required for scanning the electron beam among a plurality of reference marks.
In general, it is preferable that the relationship between a command value to be given to the deflector and the scan position of an electron beam is linear. However, in practice, the relationship may not be linear due to uneven potential between electrodes caused by production error of the electrodes constituting the deflector, a linearity error of a digital-analog converter mounted on an amplifier for driving the deflector, or the like. Thus, in the case of the lithography apparatus disclosed in Japanese Patent Laid-Open No. 7-22303 in which the resolution of the scan position of an electron beam is determined by physical spacing between reference marks, the scan position of an electron beam cannot be accurately determined when the relationship is nonlinear.